1. Field of the Invention
The present invention relates to a reproducing apparatus, and more particularly to a technique of processing ID data in a reproduced signal.
2. Related Background Art
A digital VTR is known as an apparatus of this type, in which a digital image signal is recorded in and reproduced from a magnetic tape.
In such a digital VTR, a predetermined amount of main data (audio and visual data) is added with sync data and ID data to form a sync block. Recording/reproducing is performed in the unit of each sync block.
Each sync block is added with parity codes as error correction check codes to correct any error in a reproduced signal in the unit of each sync block.
The ID data added to each sync block contains important information such as information representative of the position of a sync block on a display screen. Therefore, ID data is added with ID parity data to detect and correct any error in the ID during reproduction.
During the reproduction, if an ID parity check shows that the ID data contains an uncorrectable error, it is judged that the address indicated by the ID data is an error, and the address of this sync block is presumed from the ID data of another sync block. In accordance with this presumed address, the reproduced signal is written in a memory to thereby recover the original data.
However, depending upon the type of errors of ID data, even if the ID parity check shows no error, a real error or so-called correction error may occur.
In this case, since the ID parity check shows no error, the reproduced signal is written in the memory at an address indicated by the ID data.
Since the reproduced signal is written in the memory at the address different from the correct address, this reproduced signal is output as large noises if the reproduced signal written at the incorrect address is not corrected by the error correction process using the parity codes.
It is an object of the present invention to solve the above problem.
It is another object of the present invention to reliably detect any error in ID data.
Under such objects, a preferred embodiment of the invention discloses a reproducing apparatus comprising reproducing means for reproducing digital data from a recording medium formed with a number of tracks, the digital data including information data and ID data, the ID data including track position information of a track recorded with the information data; supplying means for supplying comparison data for a position of a track from which the digital data is reproduced by the reproducing means; checking means for checking a reliability of the ID data by using the comparison data and the track position information in the ID data reproduced by the reproducing means; and error correcting means for correcting any error in the information data.
It is a further object of the present invention to prevent the quality of a reproduced signal from being lowered by errors.
The other objects and features of the present invention will become apparent from the following detailed description of preferred embodiments when read in conjunction with the accompanying drawings.